暗目标(DT)和深蓝色(DB)算法已应用于VIIRS,以构建大气气溶胶的长期气候数据记录。这项研究提供了基于第3版1.5级AERONET测量的全球陆地上两种更新的VIIRS气溶胶产品的首次评估和比较。总的来说,两种AOD产品都与相关系数>0.85的AERONET测量结果非常吻合,并且超过75%的AOD匹配结果落在预期误差(EE)之内。DB产品优于DT产品,具有更多的AOD匹配满足EE。同时,DBAOD在时空精度上表现更好,适应不同的气溶胶类型,并解决了大视图几何体的影响。DTAOD在北半球和常绿阔叶林地区的夏季月份显示出比DBAOD更高的准确性。两种产品表现出相似的AOD空间分布模式,但是在DT产品中可以看到更高的值,尤其是在亚洲和北美西部。DBAOD的空间完整性高于DT,特别是在较亮的表面区域。相比之下,在植被丰富的地区发现了DTAOD的较高时间完整性。2020年美国西部野火的案例研究表明,这两种产品都可以捕获极端烟雾气溶胶。此外,DBAOD在空间和时间连续性以及显示烟雾气溶胶的区域传输方面显示出明显的优势。然而,在稀疏植被区域,两种产品的AOD检索精度仍需提高,北半球的夏天,细颗粒气溶胶,在极端气溶胶事件期间。对DBSSA和AE产品的总体评估表明,它们不适合进行定量科学研究。这项研究可以为用户提供如何为不同的研究目的选择VIIRS气溶胶产品的指南。
The dark target (DT) and deep blue (DB) algorithms have been applied to the
VIIRS to construct a long-term climate data recording of atmospheric aerosols. This study provides the first evaluation and comparison of two updated
VIIRS aerosol products over global land based on Version 3 Level 1.5 AERONET measurements. Overall, both AOD products agree well with AERONET measurements with correlation coefficients >0.85 and over 75 % of AOD matchups falling within the expected error (EE). The DB product is superior to the DT product with more AOD matchups meeting the EE. Meanwhile, the DB AOD performs better in spatiotemporal accuracy, adaption to different aerosol types, and addresses the effects of large view geometry. DT AOD shows higher accuracy in the summer months in the northern hemisphere and evergreen broadleaf forest areas than DB AOD. The two products exhibit similar spatial distribution patterns of AOD, but higher values are seen in the DT product, especially in Asia and Western North America. The spatial completeness of the DB AOD is higher than DT, especially in brighter surface regions. In contrast, higher temporal completeness of the DT AOD is found in vegetated areas. A case study of the Western United States wildfires in 2020 indicates both products can capture extreme smoke aerosols. In addition, the DB AOD shows a distinct advantage in spatial and temporal continuity and in displaying the regional transport of smoke aerosols. However, the accuracy of the AOD retrieval for both products still needs to be improved in sparse vegetation regions, northern hemisphere summers, fine particle aerosols, and during extreme aerosol events. The overall evaluation of DB SSA and AE products shows that they are unsuitable for quantitative scientific research. This study can provide users a guide on how to select
VIIRS aerosol products for different research purposes.